1. Field of the Invention
The present invention relates to a semiconductor device and a fabrication method therefor, and, in particular, to a semiconductor device that enables microminiaturization and has a contact structure using aluminum, and to a fabrication method therefor.
2. Description of Background Art
In a semiconductor device such as a LSI, recent advances in microminiaturization, integration, and multi-layering of elements have made it necessary to use connection through-holes such as contact holes and via-holes having high aspect ratios. Filling such connection through-holes with wiring materials is very difficult and, therefore, has become an important technical challenge in recent years. In this regard, attempts have been made to fill connection through-holes with aluminum or aluminum alloys that are useful as a wiring material.
One of the techniques intended for the above requirement is disclosed, for example, in Japanese Patent Application Laid-Open No. 64-76736/1989. This discloses a fabricationmethod in which aluminum is made to fill connection through-holes in a two-step manner, wherein aluminum or an aluminum alloy is first deposited at a temperature of 150.degree. C. or lower, then a further layer of the aluminum or aluminum alloy is grown by bias sputtering.
With this technique, aluminum layers can be deposited comparatively uniformly into connection through-holes and the coverage performance thereof is improved somewhat. However, this has not improved far enough the problem of discontinuity that occurs at conductive parts within the connection through-holes due to causes such as voids.